Extracorporeal membrane oxygenation for patients with electrical storm or refractory ventricular arrhythmias: Management and outcomes.

Patients on veno-arterial extracorporeal membrane oxygenation (VA-ECMO) are at high risk for ventricular arrhythmias due to derangements in myocardial perfusion, hemodynamics, and heightened catecholamine states. Existing data on the management and outcomes of patients with electrical storm or refractory ventricular tachycardia/fibrillation (VT/VF) treated with VA-ECMO are primarily derived from retrospective observational studies. Typical survival rates are in the range of 40-50%, with 15-20% of patients undergoing VT ablation and 30-40% of patients requiring advanced heart failure therapies (cardiac transplant or durable left ventricular assist device).

Utility of Substrate Mapping Using Extrasystole to Localise Comprehensive Ventricular Tachycardia Circuits: Results From Intra-operative Mapping Studies.

Background: Substrate mapping-based identification of all ventricular tachycardia (VT) circuits (diastolic activation), including partial and complete diastolic circuits in clinical and nonclinical VT, could be beneficial in guiding VT ablation to prevent VT recurrence. The utility of extrasystole induced late potentials has not been compared with late potentials in sinus rhythm (SR) and right ventricular pacing (RVp).

Methods: Intraoperative simultaneous panoramic endocardial mapping of 21 VTs in 16 ischemic heart disease patients was performed with the use of a 112-bipole endocardial balloon.

Orientation of conduction velocity vectors on cardiac mapping surfaces.

Aims: Electroanatomical maps using automated conduction velocity (CV) algorithms are now being calculated using two-dimensional (2D) mapping tools. We studied the accuracy of mapping surface 2D CV, compared to the three-dimensional (3D) vectors, and the influence of mapping resolution in non-scarred animal and human heart models.

Methods And Results: Two models were used: a healthy porcine Langendorff model with transmural needle electrodes and a computer stimulation model of the ventricles built from an MRI-segmented, excised human heart.

Multi-Axes Lead With Tetrahedral Electrode Tip for Cardiac-Implantable Devices: Creative Concept for Pacing and Sensing Technology.

Background: We developed a multi-axes lead (Max) incorporating 4 electrodes arranged at the lead-tip, organized in an equidistant tetrahedron. Here, we studied Max performance in sensing, pacing, and activation wavefront-direction analysis.

Methods: Sixteen explanted animal hearts (from 7 pigs, 7 sheep, and 2 rabbits) were used.

High density intramural mapping of post-infarct premature ventricular contractions and ventricular tachycardia.

Background: Spontaneous ventricular premature contractions (PVCs) and ventricular tachycardia (VT) in the acute post infarct milieu is assumed to be due to automaticity. However, the mechanism has not been studied with intramural mapping.

Objective: To study the mechanism of spontaneous PVCs with high density intramural mapping in a canine model, and to test the hypothesis that post-infarct PVCs and VT are due to re-entry rather than automaticity.

Safety, efficacy, and monitoring of bipolar radiofrequency ablation in beating myopathic human and healthy swine hearts.

Background: The safety and efficacy parameters for bipolar radiofrequency (RF) ablation are not well defined.

Objective: The purpose of this study was to investigate the safe range of power, utility of transmyocardial bipolar electrogram (EGM) amplitude, and circuit impedance in ablation monitoring.

Methods: Sixteen beating ex vivo human and swine hearts were studied in a Langendorff setup.

The Role of Ablation in Prevention of Recurrent Implantable Cardioverter Defibrillator Shocks in Patients With Tetralogy of Fallot.

Background: Implantable cardioverter defibrillators (ICDs) are effective in preventing arrhythmic sudden cardiac death in patients with tetralogy of Fallot (TOF). Although ICD therapies for malignant ventricular arrhythmias can be life-saving, shocks could have deleterious consequences. Substrate-based ablation therapy has become the standard of care to prevent recurrent ICD shocks in patients with ischemic cardiomyopathy.

Implementation of Cardiac Stereotactic Radiotherapy: From Literature to the Linac.

Stereotactic radiotherapy (SBRT) has been applied to treat cardiac arrhythmias, but our institution had not yet implemented this technique. Here, we explain how we used implementation science and knowledge translation to provide cardiac SBRT to a critically ill patient with malignancy-associated refractory ventricular tachycardia. We reviewed the critical factors that enabled the implementation of this urgent treatment, such as the context of the implementation, the characteristics of the intervention, and the stakeholders.

Decrement Evoked Potential Mapping to Guide Ventricular Tachycardia Ablation: Elucidating the Functional Substrate.

Empirical approaches to targeting the ventricular tachycardia (VT) substrate include mapping of late potentials, local abnormal electrogram, pace-mapping and homogenisation of the abnormal signals. These approaches do not try to differentiate between the passive or active role of local signals as the critical components of the VT circuit. By not considering the functional components, these approaches often view the substrate as a fixed anatomical barrier.

Stimulation and propagation of activation in conduction tissue: Implications for left bundle branch area pacing.

Background: Characterizing wavefront generation and impulse conduction in left bundle (LB) has implications for left bundle branch area pacing (LBBAP).

Objectives: The purpose of this study was to describe the pacing characteristics of LB and to study the role of pacing pulse width (PW) in overcoming left bundle branch block.

Methods: Twenty fresh ovine heart slabs containing well-developed and easily identifiable tissues of the conduction system were used for the study.

Minimalistic strategy for coronary sinus lead implant: A single tool capable of electrophysiological mapping, pressure measurement, and angiography.

Background: Left ventricular (LV) lead implantation for cardiac resynchronization therapy (CRT) may be confounded by contrast load during attempted cannulation and lead dislodgement during guiding catheter splitting. An LV lead implant system with a steerable single catheter that completely avoids the use of guiding catheters when needed, acquires atrioventricular electrograms, measures intracardiac pressures, permits CS angiography, and has the ability to direct a coronary angioplasty wire that will lead the final delivery of LV lead into a CS tributary, may help limit contrast use and avoid lead dislodgement at CS guide sheath removal.

Methods And Results: In this article as a proof of concept, we describe the use of this minimalist technique as a first line approach in six patients who had standard indications for CRT.

Signature signal strategy: Electrogram-based ventricular tachycardia mapping.

Multiple decades of work have recognized complexities of substrates responsible for ventricular tachycardia (VT). There is sufficient evidence that 3 critical components of a re-entrant VT circuit, namely, region of slow conduction, zone of unidirectional block, and exit site, are located in spatial vicinity to each other in the ventricular scar. Each of these components expresses characteristic electrograms in sinus rhythm, at initiation of VT, and during VT, respectively.

Death, discharge and arrhythmias among patients with COVID-19 and cardiac injury.

Background: Cardiac injury is common in severe coronavirus disease 2019 (COVID-19) and is associated with poor outcomes. We aimed to study predictors of in-hospital death, characteristics of arrhythmias and the effects of QT-prolonging therapy in patients with cardiac injury.

Methods: We conducted a retrospective cohort study involving patients with severe COVID-19 who were admitted to Tongji Hospital in Wuhan, China, between Jan.

Safety and Long-term Outcomes of Defibrillator Therapy in Patients With Right-Sided Implantable Cardiac Devices in Adults With Congenital Heart Disease.

Background: Implantable cardioverter-defibrillators (ICDs) have been proven to prevent sudden cardiac death in adult congenital heart disease (ACHD) patients. Although the left side is chosen by default, implantation from the right side is often required. However, little is known about the efficacy and safety of right-sided ICDs in ACHD patients.

Trans-myocardial bipolar electrogram: A strategy for mapping and determining efficacy of bipolar ablation of deep foci.

Mapping and ablation of intramural ventricular tachycardia (VT) remain a challenge. We developed a trans-myocardial electrogram recording across distal tips of two separate ablation catheters placed on contralateral sides of the myocardium to record a trans-myocardial bipole and a novel pacing electrode configuration. This trans-myocardial bipole was applied during bipolar ablation in a patient with septal VT.